In portable devices such as a note-type personal computer, a portable telephone, a smartphone, and a tablet, a shock-absorbing sheet may be arranged at the back side of a display device for preventing breakage and failure. High flexibility is required for the shock-absorbing sheet, and a foam sheet has been widely used as the shock-absorbing sheet. As the foam sheet used as the shock-absorbing sheet, a crosslinked polyethylene foam sheet containing a large number of closed cells is known, for example, as described in PTL1. Further, a urethane foam sheet, a rubber foam sheet, and the like have also been widely used.